Plied sheet and method of producing the same



- l. J. NOVAK PLIED SHEET AND METHOD OF PRODUCING THE SAME June 12,1928. 1,672,988

Original Filled April 12. 1922 JMMKWW Patented June 12, 1928.

UNITED STATEMS 1,672,988 PATENT OFFICE.

IZADOR J'. NOVAK, F BRIDGEPORT, CONNECTICUT, ASSIGNOR TO THE R AYBESTOSCOMPANY, OF BRIDGEPORT, CONNECTICUT, A CORPORATION OF CONNECTICUT.

PLIED SHEET AND METHOD OF PRODUCING THE SAME,

Application filed April 12, 1922, Serial No. 552,022. Renewed December22, 1927.

This invention relates to improvements in plied sheet and method ofproducing the same, and refers more particularly to a sheet of feltedfibrous material in which separate plies are bonded together during theforming of the sheet by grading the stock of the separate plies in themake-up vat so that when the plies are incorporated into a fibre boardor sheeted material, the material of one ply will be graded andincorporated as a unit with the next adjoining ply.

The wet machine which is commonly used in paper and fibre boardmanufacture, consists essentially of a hollow horizontal Wire meshcovered cylinder revolving in a vat containing the pulp or stock to beformed into sheet. Upon the surface of this cylinder a layer of pulp isdeposited in its rotation by the filtering action of the wire mesh. Amoving blanket functions to pick up the film or pulp formed on thecylinder and carry it to a horizontal mandrel or make-up roll upon whichthe film is deposited and wound up to the desired thickness. This typeof machine is quite universally employed for the manufacture of fibreboards above a thickness of of an inch.

In producing a sheet of material of a lesser thickness, it is customaryto utilize what is known as a multi-cylinder paper machine. When it isdesired to produce a fibre and board material consisting of two or moredifferent types of fibre, it is the usual practice to ply it with theindividual constituent sheets of the required thickness by the use of acementitious' material such as starch, paste, glue, dextrin and similarsubstances.

The novelty in the present invention lies in the method by which aperfect interlocking bond may be formed between the separate plieswithout the aid of any cementitious agent but simply by the grading ofthe stock of one character to that of another character to beused in theadjoining ply in a manner that there is a complete interlocking of thefibrous material to produce a unitary structure.

Fig. 1 is a diagrammatic side elevational view of the apparatus. Fig. 2is a fragmentary section of the finished sheet.

Referring to the drawings, in order to produce a plied sheet by thismethod, the pulp stock of the desired composition is introduced to thevat 1 in which is mounted a 55. cylinder mould 2. The cylinder mouldserves to pick up the film of the stock and transfer it to the blanket 3which runs over a plurality of guide pulleys 4. The blanket travelingover roll 5 relieves the cylinder of the film of stock which it haspicked up, in the vat and transfers it onto the mandrel or make-up roll6. Here the ply is built up to the desired thickness. When it is desiredto impose the next overlaying ply upon the mandrel, the character of thepulp in the vat is changed by shutting off the first variety of stockand turning on a pulp stock of a different character. As this isaccomplished without stopping the machine, it will be understood thatthe composition in the vat changes successively from pure A. to pure B.,through an intermediate plying stage in which both varieties arepresent. This intermediate stage may be short or long dependent upon theamount of stock the vat is desired to contain and the rate at which acomplete change may beefl'ected.

The sheet on the mandrel will indicate the variation in the compositionof the vat stock and will change through its cross section from one kindof stock to the other, as shown in Fig. 2 of the sectional view of thesheet. When removed from the mandrel and dried, the resulting sheetcontains the two varieties of fibre of the desired position united by acomposition intermediate the two and grading from one to the other so asto a perfect union of the separate plie stocks.

It is understood that as many plies may be made as desired by thismethod conforming with the number of fibres the stock in the vat isvaried during the plying operation.

In addition to the variation in the fibrous material used in thesuccessive stocks there may also be a variation in the chemicalconstituents, colorin' matter or numerous other ingredients whic make upthe stock which is to be sheeted on the machine. The filler substance ora different colored pigment may be used in the different plies therebyvarying the character without necessarily changing the character of thefibrous material.

I claim as my invention:

1. A method of producing a sheet of two or more plies of differentcharacter upon a wet' machine, consisting in successively changing thestock to be sheeted while sheeting the stock in successive plies byconvolution.

2. A method of uniting successive plies in roduce a laminated sheet ofmaterial consisting in successively varying the stock to be sheetedwhile continuously sheeting the varied stocks and building them up insuccessive plies.

3. A laminated fibre sheet, comprising a sheeted fibrous stock of variedcomposition, said sheet having properties variant throughout its crosssection, having the characteristicsof having been made on a wet machine.

4. A laminated fibrous sheet, comprising two or more plies of fibrousmaterial of differing characteristics, the fibres of adjacent 15 pliesinterlocking to form a unitary structure to the united sheet havingproperties IZADOR J. NOVAK.

